| abstract |
(57) [Summary] [PROBLEMS] To solve the problem of crack generation at the joint between metal and ceramic, which is a cause of deteriorating the soundness of the seal of a sensor. SOLUTION: A high purity sapphire having an impurity amount of 30 ppb or less and a dislocation density and an etch pit density of 2 pits / mm 2 or less is employed as a ceramic for an electric insulator, and a bond with a metal, particularly Kovar, is formed. sensor. |